Background: Previous studies have shown that impaired pulmonary function may be associated with cognitive decline, posing the question of whether peak expiratory flow (PEF) % pred could present a modifiable risk factor. Objective: To assess the association between PEF% pred and future cognitive function among Chinese participants aged 45 years and above. Methods: Data came from four waves fielded by the China Health and Retirement Longitudinal Study. Cognitive function was assessed by a global cognition score. Multivariate linear regression models and generalized estimating equation (GEE) were used to investigate associations between PEF% pred and later cognitive function. Results: A total of 2,950 participants were eligible for the final data analysis. After adjustment for baseline cognition and potential confounders, the association remained statistically significant (beta = 0.0057, p = 0.027). Domains with increases were focused on episodic memory (beta = 0.0028, p = 0.048) and figure drawing (beta = 0.0040, p = 0.028). But these associations were not found in women (beta = 0.0027, p = 0.379). However, GEE suggested that the rates of decline in global cognition decreased by 0.0096 (p < 0.001) units per year as baseline PEF% pred increased by 1% in middle-aged and elderly individuals, regardless of sex. And higher baseline PEF% pred correlated with declined rates of decrease of in episodic memory, figure drawing, and Telephone Interview of Cognitive Status (TICS). Conclusion: Higher baseline PEF% pred was significantly associated with slower cognitive decline in global cognition, episodic memory, figure drawing, and TICS in middle aged and elderly Chinese adults.